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Old 09-06-2011, 03:46 AM   #11
mmonacel
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Jan 2010
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Quote:
Originally Posted by Denny View Post
From http://promash.websitetoolbox.com/post?id=1790768

You can calculate this yourself using ProMash.
  1. Go into ProMash and open the Strike Temp calculator.
  2. For Mash Tun Thermal Mass, Enter 0.
  3. For Total Grain enter 0.00001 pounds. (It won't let you go any smaller - entering 0 will give you a division error.) This should make your water:grain ratio 120000:1.
  4. For Total Water, enter 16.00 quarts.
  5. For Desired Strike Temp, enter 170. (You can use any temperature but this will more accurately reflect actual mash temperatures.)
  6. For Grain Temp, enter the current room temperature.
  7. Heat 16 quarts (4 gallons) of water to 170 degrees and pour it quickly into the mash tun. Close the lid and seal it up, and let it sit for about 5 minutes.
  8. Measure the temperature of the water in the mash tun.
  9. Enter the temperature of the water in the mash tun in the "Desired Strike Temp" field in ProMash.
  10. Now look at the "Initial Strike Water Temp Should Be" window. You will note that, with Thermal Mass set to 0, this number will be the same as the "Desired Strike Temp" field.
  11. Now, in small (say 0.1 or smaller) increments, increase the Thermal Mass field until the "Initial Strike Water" field reads 170 (or whatever temperature you started with, if you didn't use 170 for some reason.).
  12. Ta-da! Whatever the Thermal Mass field says is your mash tun's thermal mass!
Anyone have this same process for BeerSmith (2.0 preferrably)? I've searched around but to no avail.
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Old 09-07-2011, 12:07 AM   #12
mmonacel
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Shameless bump. Surely someone's tweaked their thermal mass / specific heat in BeerSmith...
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Old 02-28-2012, 08:48 PM   #13
malweth
 
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Sorry to deep res this thread -- found it on a search

I just did this on paper for my own use...

You can follow the same steps. You're interested in the following measurements:

I assume Beer Smith calculates thermal mass in calories -- I don't have the program installed at work to check.

1. Weight of water (in grams) (Mw)
2. Initial Temperature of Mash Tun (Tt) (temp. units don't matter - they'll cancel)
3. Initial Temperature of Water (Tw)
4. Final Temperature of Water (Tf)

The equation for thermal energy (see Beer Smith documentation)
MwTw + MtCtTt = (Mw + MtCt)Tf

All values are known except MtCt, which is the thermal mass of the tun.

Solving for MtCt:
MtCt = Mw (Tf - Tw) / (Tt - Tf)

All values on the right side of the equation are known.
If Beer Smith requires the tun's weight, you can weigh it and find out the specific heat -- or just use a dummy value. This will work, but it's not actually correct.

This has been my problem with this value all along (and is part of why I've gone and figured it out -- also, I'm learning Android programming )... a cooler is an inner wall and an outer wall with insulation between. The thermal mass really consists of only the inner wall and some of the insulation -- insulation likely has low thermal mass, but the rate of heat transfer is decreased. This emulates a closed system for a period of time.
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Old 10-04-2012, 09:42 PM   #14
JDoubleDuBB
 
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Aug 2012
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Quote:
Originally Posted by swankyswede View Post
If calculating it is your jam, by all means grab your pencil and TI-83 and calculate away.
This is awesome! Well said sir, well said.

 
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Old 10-04-2012, 09:49 PM   #15
FuzzeWuzze
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Quote:
Originally Posted by mmonacel View Post
Shameless bump. Surely someone's tweaked their thermal mass / specific heat in BeerSmith...
Ive found that entering in the 10G Igloo coolers true weight(9lbs) and using the .30 Cal/Gram-deg C Mash Tun Specific Heat for plastic results in dead on temps when using an unheated mash tun.

 
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